Range hood fan having filter

ABSTRACT

A range hood fan is constituted of a case main body connected partly to an exhaust gas duct and forming an exhaust gas passage inside the case main body, a fan motor supported by a partition wall in the case main body and having a fan on a rotation shaft, and an exhaust gas suction opening formed in a portion open in a hood main body of the case main body. A first filter is provided at the lower part of the case main body. The first filter is formed by net structure through which gas containing oily smoke can be passed and has first grooves which are extended in a rotation direction of the fan and end portions of which are open in the exhaust gas passage. A second filter is provided inside the first filter. The second filter is formed by net structure through which gas containing oily smoke can be passed and has second grooves that are larger than the first grooves and are open in the exhaust gas passage. The gas sucked by the fan through the exhaust gas suction opening is caused to flow along each of the second grooves and of the first grooves, so that oily smoke is liquefied and collected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national entry application of International PatentApplication Serial No. PCT/JP2003/008307 entitled “Range Hood Fan HavingFilter” to Yoshihiro Yamada filed on Jun. 20, 2003, and thespecification and claims thereof are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The present invention relates to a fan used in a range hood forevacuating air or gas, which contains oily smoke generated duringcooking with cookers such as pots or pans (the gas includes vapor, andexhaust gas in the case of a gas range), to the outside of a house.

2. Description of Related Art

In a kitchen, gas such as exhaust gas from gas burning and vaporincluding oily smoke and odor is released during cooking with variouscookers such as pots and pans. If such oily-smoke-containing gas is notevacuated to the outside of a house, the gas results in a deteriorationof combustion efficiency and a hypoxia state which adversely affectshuman health, and also the oily smoke stains the room. Therefore, suchoily-smoke-containing gas is usually F evacuated to the outside by aventilation fan, or by a blower from an exhaust duct through a rangehood installed above the cookers.

In particular, comparing with the use of a ventilation fan, the methodusing a range hood can guide the oily-smoke-containing gas efficientlywith the range hood, thus can be used in a so-called “system kitchen”.Moreover, this is very advantageous as an exhaust method because it cansecure to evacuate the oily-smoke-containing gas by getting a range hoodcloser to the source of the oily-smoke-containing gas.

However, in a conventional evacuation method using such a range hood,the following problems has yet to be solved; problem 1, noise inoperation, problem 2, disposal of oily smoke which causes stains onouter walls near the opening of the exhaust gas duct, and stains insidethe device.

First of all, in view of the noise problem, although a general rangehood has an enough size to cover cookers, the evacuating duct forevacuating oily-smoke-containing gas sucked from the hood has a limitedsize of 15 cm in diameter. Therefore, a blower must be a large size,which tends to generate noise, also it is understood that noise isgenerated when the oily-smoke-containing gas hits or contacts thevarious places of the gas passage.

In addition, when the oily-smoke-containing gas is sucked by a vacuumapparatus, if there are complex obstacles in the passage of the gas,these obstacles not only lower the suction efficiency by raising suctionresistance, but also cause such noise as mentioned above. Morespecifically, because an exhaust gas duct must be lead through walls andthe ceiling to be opened to the outdoor, a diameter of the exhaust gasduct must be small comparing with the opening space of the range hood asdescribed above. Thus, some kinds of measures have to be taken to suckthe oily-smoke-containing gas toward the duct having a small diameterwithout any obstacles, and evacuate the gas.

In particular, in a kitchen provided with an intake system as well as anexhaust system, a exhaust system having ability of about 400 m³/h isenough for evacuating only exhaust gas, but an exhaust system havingability of 500 m³/h is required for evacuating oily smoke as well asexhaust gas. However, because there are few kitchens provided with sucha intake system separately, an exhaust system capable of evacuating oilysmoke as well as exhaust gas requires ability of about 700 m³/h at themaximum. The above-mentioned noise cannot be avoided in the case of theevacuation through the exhaust gas duct by using such an exhausterhaving high ability.

Therefore, we may adopt a so-called Sirocco fan as a device having alarge displacement volume but causing little noise. However, since thesize of such a general Sirocco fan, including its casing, isconsiderably big, the design structure of a range hood and the overallsystem kitchen have to be changed when it is installed in the range hoodhaving a small size or in other place. However, at the current situationit is almost impossible to change the design including the size of therange hood and other parts within the kitchens with a limited space,thus such a Sirocco fan cannot be utilized or adapted for the kitchen asit is.

Therefore, the inventor made an invention suggested in Japanese Patentpublication No. 2609280 after various considerations as to exhaustsystems capable to solve the above first problem, i.e., to reduce thenoise significantly while fully keeping the advantages of the exhaustmethod using a range hood.

BRIEF SUMMARY OF THE INVENTION

This invention already suggested is as follows: an exhaust device todraw in fumed air produced from cocking on a cooking range in a kitchenand to expel said fumed air into an exhaust duct, comprising: a vent boxconnected with said exhaust duct in fluid communication therewith, whichis installed in one of a range hood and in a housing box connected witha range hood in fluid communication therewith; and a drawer devicehoused in said vent box, wherein said vent box includes a connectionenclosure in an upper portion thereof in fluid communication with saidexhaust duct which converges toward said exhaust duct, wherein a pair ofsubstantially vertical partitions are provided within said vent box onopposite sides from the longitudinal axis of said vent box, each havinga titled plate extending toward a central crossline of an opening ofsaid exhaust duct, provide a pair of vent routes together with sidewalls of said vent box, said vent routes converging toward said exhaustduct, wherein said drawer device comprises: a drive motor; a pair ofdrive shafts protruding substantially horizontally in oppositedirections from said drive motor correspondingly into said vent routesthrough said partitions; and a pair of Sirocco fans having bladescorrespondingly mounted on said drive shafts in said vent routes, eachset of said blades converging toward said drive motor.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the specification, illustrate one or more embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the invention. The drawings are only for the purpose ofillustrating one or more preferred embodiments of the invention and arenot to be construed as limiting the invention. In the drawings:

FIG. 1 is a fragmentary vertical cross-sectional view, which illustratesa kitchen provided with a range hood 200 having a range hood fan 100according to the present invention.

FIG. 2 is an enlarged right side elevation view of the range hood fan100 in the range hood 200.

FIG. 3 is a left side elevation view of the range hood fan 100.

FIG. 4 is a front elevation view of the range hood fan 100.

FIG. 5 is a rear elevation view of the range hood fan 100.

FIG. 6 is a plane view of the range hood fan 100.

FIG. 7 is the bottom plan view of the range hood fan 100.

FIG. 8 is an enlarged transverse cross-sectional view taken along 1-1line of FIG. 2.

FIG. 9 is an enlarged vertical longitudinal sectional view taken along2-2 line of FIG. 6.

FIG. 10 is an enlarged partial transverse cross-sectional view takenalong 3-3 line region of FIG. 8.

FIG. 11 is a partial cutaway left side elevation view to show the stateof opening of an opening and closing lid 20 provided under a case mainbody 10.

FIG. 12 is a longitudinal sectional view illustrating a prior art. FIG.13 is a longitudinal sectional view illustrating another prior art.

EXPLANATIONS OF THE LETTERS OF NUMERALS

100  range hood fan  40 first filter 10 case main body  41 first grooves11 evacuating opening  41a end portion 12 partition wall  42 firstfilter passage 13 duct joint  50 second filter 14 exhaust gas passage 51 second grooves 15 exhaust gas suction opening  51a end portion 16damper  52 second filter passage 20 opening and closing lid 200 rangehood 21 oil pits 210 hood main body 22 hinge 220 exhaust gas duct 23stopper screw 230 filter 30 fan motor 300 cooker 31 rotation shaft 310gas range or electromagnetic range 32 fan 410 ceiling  32a blades 420wall

DETAILED DESCRIPTION OF THE INVENTION

The exhaust system, which the inventor of the present invention alreadysuggested in Japanese Patent No.2609208, is thus able to solve the abovefirst problem. However, after the later examination, the possibilitythat it does not solve sufficiently the above second problem concerningoily smoke was found.

Now, in view of the above second problem concerning oily smoke, in ageneral range hood, a filter 230 is provided in a hood main body 210,and the filter liquefies oil or oily particles of oily smoke suckeddirectly and turn it into oil droplets to collect the same. However, itis impossible to catch all the oil or oily particles by the filter 230provided in the hood main body 210, thus the remaining oil or oilyparticles are sucked up by a range hood fan installed behind the filter230 and smears blades and other parts comprising of this range hood.

It is difficult to clean a general range hood fan which is installedinside of the filter 230, and besides it is almost impossible to cleanthe blades which are inside of the range hood fan. On this account, asthe oil droplets attached on each blade accumulate gradually, it may bea cause for losing the function of the range hood fan itself.

Therefore, in Japanese Patent Laid-Open Publication No. 2000-104969, “afan casing for multiblade fan in a simple structure to improveperformance for collecting oil” was proposed. This fan casing as shownin FIG. 12 has an air flow touch area enlarged to the both front andback sides of air guide 4 placed in casing 1 as well as inside of thecasing 1″ and it is conceivable that “it can provide the fan casing,which improves the efficiency of capturing oil and fat content and doesnot get clogged, at a low price with a simple structure without addingany modifications for the main body and right and left side plate”(description of paragraph 0021 of the above publication).

However, as the above description, when the air flow (theoily-smoke-containing gas) comes in contact with not only the innersurface of the casing 1, but also the air guide 4 formed inside of thecasing 1, it can be considered as a cause of noise, thus it may not beable to solve the above first problem of noise.

In paragraph 0011 in the above-cited publication it is described that“the edge of entrance of an air guide 4 is made as a slanting edge,jaggy edge and the like to change the timing of air collision in thecase of the inflow, thus prevent from generating noise by air collidingto the full length of the entrance edge 4 a′ simultaneously”. However,even though it can achieve some prevention of noise at the entrance ofthe air guide, the noise prevention effect cannot be expected in totalbecause the prevention of the noise can be done only as part of the longair guide 4. In addition, it should be understood that merely flowingoily-smoke-containing gas on the surface of the flat air guide 4 is notenough to collect and catch the oil or oily particles of the oily smoke.As such it is hard to believe that its technology solves the secondproblem concerning oily smoke.

In addition, in Japanese patent No. 3,009,649, “a range hood” issuggested as shown in FIG. 13 for the purpose of “providing a range hoodwhich can improve the capture efficiency of oil and fat content withoutraising pressure loss, and also prevent the oil and fat content fromflowing out to the duct side”.

The conventional range hood shown in FIG. 13 has “a fan casing having acorrugated inner surface of a fan casing installing a fan of a blowerequipped in the hood” (claim 1), in particular, as disclosed in claim 4,“the said corrugated surface of the body is formed alternatively andcontinuously so as to cross the flowing direction of the air(oily-smoke-containing gas) generated by the rotation of the fan”.

Then oily-smoke-containing gas sucked in the fan casing collides withthe corrugated surface, thus it is considered that noise occurs by theair collision to the corrugated surface like the conventional embodimentshown in FIG. 12, although the oily smoke can be caught.

Thus, the inventor completed the present invention after repeatedexaminations in various ways to perform the collection of oil fromoil-containing smoke effectively and greatly reduce noise while theadvantages of an exhaust method using a range hood is kept.

That is, the purpose of the present invention is to provide a range hoodfan 100 capable to catch oil or oily particles of oily smoke, which isnot caught by a general filter in the upstream, and also noise is notgenerated at the time of this procedure of catching the oil or oilyparticles, i.e. even though oily-smoke-containing gas flows.

In order to solve the above-described problems, the present inventionhas been developed, and the invention described in claim 1 employs thefollowing means as described below being attached with referencenumerals, which are used in the description of best mode for carryingout the invention described later; that is, “a range hood fan (100),which is used in a range hood (200) collecting oily-smoke-containing gasgenerated from cookers such as pots and pans during cooking, andevacuating the oily-smoke-containing gas to the outdoor through anexhaust gas duct (220), and is installed in a hood main body (210). Therange hood comprises a case main body (10) connected partly to anexhaust gas duct (220) and forming an exhaust gas passage (14) insidethe case main body, a fan motor (30) having a fan (32) on a rotationshaft (31) and being supported by a partition wall (12) in the case mainbody (10), and an exhaust gas suction opening (15) formed in a portionopening in the hood main body (210) in the case main body (10). Therange hood further comprises a first filter (40) being provided at alower inside part of the case main body (10) by net structure throughwhich the only smoke containing gas can be passed and having firstgrooves (41) extended in a rotation direction of the fan (32) and endportions of which are open in a exhaust gas passage (14), and a secondfilter (50) provided inside the first filter (40), the second filter(50) being formed by net structure through which theoily-smoke-containing gas can be passed and having second grooves (51)that are larger than the first grooves (41) and end portions of whichare open in the exhaust gas passage (14). The first filter (40) and thesecond filter (50) liquefies and collects oil or oily contaminants fromthe oily smoke of the gas by flowing the gas, which sucked from exhaustgas suction opening by a fan (32), along each of the second grooves (51)and of the first grooves (41).”

That is, this range hood fan 100 comprises the first filter 40 andsecond filter 50 formed by net structure on the inner surface of thelower inside part of the case main body 10 as shown in FIG. 8-FIG. 10,the first filter 40 having the first grooves 41 and the second filter 50having the second grooves 51. Particularly, in the range hood fan 100 ofthis invention, as shown in FIG. 10, each of the second grooves 51 isdeeper than each of the first grooves 41, and the first filter 40 andthe second filter partly contact with each other.

In the range hood fan 100 constructed as above, when the fan motor 30rotates, a fan 32 attached to the rotation shaft starts rotating, andgas caught by a hood main body of the range hood 200 starts being suckedfrom a exhaust gas suction opening 15 formed in the case main body 10 ofthe range hood fan 100. Because part of oil and oily particles ofoily-smoke-containing gas is caught primarily by the filter 230installed in the food main body 210, the oily smoke is reduced by thetime it reaches a exhaust gas suction openings 15. However the oilysmoke is not eliminated completely.

The oily-smoke-containing gas sucked from each of the exhaust gassuction openings 15 by the rotation of fan 32 as mentioned above flowsin a exhaust gas passage 14 in the case main body as shown with outlinearrows in FIG. 9. At this stage, as shown with outline arrows in theleft side of FIG. 9, most of the oily-smoke-containing gas gets into thefirst filter 40 and second filter 50 from the left end of FIG. 9 asshown, and the remaining oily-smoke-containing gas flows along thesurface of the second filter 50 (the surface facing the fan 32). Ofcourse, because each of the first filter 40 and second filter 50 is madeof, for example, a metal net structure, the flowingoily-smoke-containing gas sufficiently passes through each net structurefrom the inside of the first filter 40 and second filter 50 to theoutside, or the other way around.

Because the oily-smoke-containing gas flowing along the surface of thefirst filter 40 and second filter 50 and passing these filters asmentioned above naturally contacts and passes each net structure of thefirst filter 40 and second filter 50, the oil and oily particles of oilysmoke liquefied and gets caught by the first filter 40 or the secondfilter 50. In the range hood fan 100 as shown in the best mode describedbelow, the oil and oily particles caught is collected in a oil pit 21placed at the bottom part of the case main body 10.

Importantly, the range hood fan 100 does not become a source of noisebecause it does not generate a big noise when the oily-smoke-containinggas contacts the surface of the first filter 40 and second filter 50 andpasses these net structures. The first reason for the above is that thefirst grooves 41 formed in the first filter 40 and the second grooves 51formed in the second filter 50 make a smooth flow of theoily-smoke-containing gas. The second reason for the above is that thefirst filter 40 and second filter 50 are actually “filters” with netstructures.

For the detail of the first reason, as shown in FIG. 9, because thefirst grooves 41 of the first filter 40 and the second grooves 51 of thesecond filter 50 are dented in the flowing direction of theoily-smoke-containing gas shown with outline arrows in the drawing, thefilters do not provide resistance for the flow of theoily-smoke-containing gas as shown in FIG. 10, thus theoily-smoke-containing gas passes smoothly through the filters. Inaddition, the second grooves 51 of the second filter 50 is formed deeperthan the first grooves 41 of the first filter 40, and the second filter50 is in close contact with the first filter 40 as shown in FIG. 10.Therefore, even if the force of the oily-smoke-containing gas is addedon the second filter 50 and first filter 40, these filters do notvibrate each other, thus do not generate noises.

Then, for the detail of the second reason, because each of the firstfilter 40 and second filter 50 is a filter having net structure, theflow of oily-smoke-containing gas enters and leaves the first filters 40and the second filter 50 freely. Thus, in the flow of theoily-smoke-containing gas, a big resistance, which can be a source ofnoise, is not generated by the first filter 40 and second filter 50. Inaddition, even if a turbulence in the flow of oily-smoke-containing gasoccurred, the turbulence is rectified and put out by the first filter 40and second filter 50, thus the noise is not generated by the turbulence.From the above reasons, each of the first filter 40 and second filter 50does not generate noise by the oily-smoke-containing gas flow.

When the gas contacts the surface of such first filter 40 and secondfilter 50 and passes the net structure thereof, the oil or oilyparticles in the oily-smoke-containing gas is liquefied as is the casewith the filter 230 installed in the hood main body 210. The liquefiedoil flows to the oil pit 21 along the first filter 40 and second filter50 and is corrected in the oil pit 21.

Thus, the range hood fan 100 disclosed in claim 1 removes most of theoil or oily particles of the oily-smoke-contained gas entered into thecase main body 10 through the filter 230 placed in the hood main body210, while it reduces noise. As a result, the exhaust gas from theexhaust gas duct 220 contains no oily smoke, thus the outer wallsurfaces of a building does not get stained.

Now, the invention disclosed in claim 2 is explained below. Thisinvention of claim 2 is characterized by “a bottom of the case main body(10) having a opening and closing lid (20) opening a exhaust gas passage(14), and the first filter (40) and the second filter (50) beingdetachably attached on an inner surface of the opening and closing lid(20)” as to the range hood fan 100.

That is, in the range hood fan 100 according to claim 2, the above firstfilter 40 and second filter 50 are attached detachably on the innersurface of the opening and closing lid 20 as shown in FIG. 9 and FIG.10, the opening and closing lid 20 being openable and closable to thecase main body 10 as shown FIG. 1 and FIG. 11.

As a result of the above, in the range hood fan 100 according to claim2, the first filter 40 and second filter 50 attached on the innersurface of the opening and dosing lid 20 can be detached from the hoodmain body 210 by opening the lid 20 as shown in FIG. 11. That is, whenthe maintenance such as the exchange and cleaning of the filter 230 inthe hood main body 210 is conducted, the maintenance of the first filter40 and second filter 50 of the range hood fan 100 can be also conductedat the same time.

Thus, the range hood fan 100 according to claim 2 produce the identicalfunction as in the case of the range hood fan 100 of claim 1, and alsothe maintenance of the first filter 40 and second filter 50 of the rangehood fan 100 can be easily performed according to the invention of claim2.

THE BEST MODE OF CARRYING OUT THE INVENTION

Now, the range hood fan 100 according to the best mode shown in thedrawings will be described below, then it should be understood that thisrange hood fan 100 of the best mode substantially includes all theabove-mentioned invention.

FIG. 1 shows a kitchen which has a range hood 200 installed near theceiling 410, the range hood 200 includes the range hood fan 100 of thisinvention. In this kitchen, cookers such as pots and pans are heated bya gas range or an electromagnetic cooker 310 placed attaching to thewall 420. Capture of oily-smoke-containing gas generated from eachcooker is facilitated by sucking the gas by the range hood fan 100installed in the range hood 200, and also by evacuating the gas from aexhaust gas duct 220.

When this range hood 200 is sucking the oily-smoke-containing gas, someof the oily smoke (oil or oily particles) is removed by a filter 230provided in hood main body 210. However the oily smoke cannot be removed100%, thus the rest of the oily smoke is sucked into the range hood fan100 of the present invention.

As shown in FIG. 2-11, the range hood fan 100 is constituted of a casemain body 10 connected partly to an exhausting duct 220 and forming anexhaust gas passage 14 inside the case main body, a fan motor 30supported by a partition wall 12 in the case main body and having a fan32 on a rotation shaft 31, an exhaust gas suction opening 15 formed in aportion opening in the hood main body 210 of the case main body 10. Afirst filter 40 is provided at the lower part of the case main body 10by net structure through which oily-smoke-containing gas can be passedand has first grooves 41 extended in a rotation direction of the fan 32and end portions of which are open in a exhaust passage 14. A secondfilter 50 is provided inside the first filter 40. The second filter isformed by a net structure through which oily-smoke-containing gas can bepassed and having second grooves 51 that are larger than the firstgrooves 41 and end portion of which are open in the exhaust passage 14.

The case main body 10 of the range hood fan 100 hermetically includesthe fan motor 30 and the fan 32 within thereof. The upper end of thecase main body is a duct joint 13 for connecting with the exhaust duct220 opened to the out door. The inside of the duct joint 13 is anevacuating opening 11. Further, at both right and left side of the casemain body 10, as shown in FIG. 2 and FIG. 3, exhaust gas suctionopenings 15 are opened to suck oily-smoke-containing gas caught by food210. In addition, a damper 16 intercepting fresh air coming through theexhaust duct 220 is provided in the evacuating opening 11 of the casemain body 10.

Further, at the lower part of the case main body 10, the opening andclosing lid 20 is provided in the form that it can be opened and closedas shown in FIG. 1 and FIG. 11, and is attached to the case main body 10with a hinge 22 as shown in FIGS. 9 and 11. In addition, this openingand dosing lid 20 is fixed to the case main body 10 with a stopper screw23 provided at the other side of the hinge 22.

The partition wall 12 is provided at the center of the case main body 10as shown in FIG. 8. The both sides of this partition wall 12 are theexhausting gas passages 14 connected to the evacuating opening. Inaddition, this partition wall 12 supports a fan motor 30 as shown inFIG. 8, and is set in the position that the fan 32 fixed to the rotatingshaft 31 of the fan motor is stable within either side of the partitionwall 12.

In addition, fan 32 are so-called “Sirocco fan” provided with blades 32a extended in the direction of the rotation axis 31 of the fan motor 30,each of the blades 32 a being slanted outward as it goes to each exhaustgas opening 15. By constructing the fan 32 in this manner, the suctionforce by the fan 32 is raised, and the generation of noise by forwardingoily-smoke-containing gas is prevented.

The range hood fan 100 of this invention is provided with the firstfilter 40 and the second filter 50 exposed to the exhaust path 14comprised of the case main body 10 as shown in FIG. 8, 9. According tothe best mode, these first filter 40 and second filter 50 are removablyattached to the inner surface of the opening and closing lid 20, thuscan be removed from this opening and closing lid 20 when maintenance isnecessary. These first filter 40 and second filter 50 made of metal netor perforated metal, each mesh of the net structure of the second filter50 is larger than that of the first filter 40 so as to make it easierfor the oily-smoke-containing gas to reach the first filter 40 throughthe second filter 50.

The first filter 40 near the opening and closing lid 20 is formed with anumber of the first grooves 41 as shown in FIG. 10, and the spacebetween these first grooves and the opening and closing lid 20 formsfirst filter passages 42. Each of the first grooves 41 having a longshape is extended to the rotation direction of the fan 32 as shown inFIG. 9, thus the grooves 41 are hard to become resistance against theflow of the oily-smoke-containing gas, and also have a large contactsurface to the oily-smoke-containing gas. In addition, both ends 41 a ofeach of the first grooves 41 open to the exhaust gas passage 14 formedin the case main body 10 as shown in FIG. 9, so that the induction ofgas to the first filter passages 42 and derivation of gas from the firstfilter passages 42 can be performed without resistance.

The second filter 50 directly facing the exhaust gas passage 14 isformed with a number of the second grooves 51 along the current of thegas, the second grooves 51 is deeper than the first grooves 41 and, inthe best mode, the size is about the size that two first grooves 40 ofthe first filter 40 can get into a second grooves 51. Of course, thesecond filter passages 52 are formed between the second grooves 51 asshown in FIG. 10, and the both ends 51 a of the second filter 50 open tothe exhaust gas passage 14 as shown in FIG. 9. As a result, as is thecase of the first filter 40, the second filter 50 makes the resistanceagainst oily-smoke-containing gas lower by the second grooves 51 formedalong the flowing direction of oily-smoke-containing gas, and induce andevacuate the oily-smoke-containing gas by the both ends 51 a.

Because the first filter 40 and second filter 50 each have a netstructure, it goes without saying that oily-smoke-containing gas canmove freely between these filters. Thus, even if a turbulence of theoily-smoke-containing gas is generated within the case main body 10, theturbulence cannot be constant because this turbulence moves freelythrough each mesh of the net structure. Thus, the oily-smoke-containinggas passes the net structure or contact to the surface of the firstfilter 40 and second filter 50, and the oil or oily particles with inthe smoke is caught by the first filter 40 or the second filter 50 andliquefied. The liquefied oil or oily particles goes to the inner surfaceof the opening and closing lid 20 along the first filter 40 and secondfilter 50, and the liquefied oily smoke is collected in a oil pit 21provided at the lid.

In the range hood fan 100 in accordance with the best mode, as shown inFIG. 9, a part of the exhaust gas passage 14, where theoily-smoke-containing gas first contacts or passes the first filter 40and second filter 50 is formed to be narrower than a part of exhaust gaspassage 14, which is located at the back end of the first filter and thesecond filter. Therefore, at the part near the evacuating opening 11 ofthe case main body, the pressure of the oily-smoke-containing gasbecomes low, and the oily smoke in the gas is easy to be liquefied, thusit is secured that the first filter 40 and second filter 50 can catchand liquefy the oily smoke. In contrast, most of oily-smoke-containinggas forwarded by the fan 32 goes into the first filter passages 42 ofthe first filter 40 and the second filter passages 52 of the secondfilter 50 due to the narrowed shape of the both end of 41 a and 51 a inthe left side of FIG. 9.

INDUSTRIAL APPLICABILITY

The invention is further illustrated by the following non-limitingexamples.

Because a range hood fan 100 constructed as above according to claim 1comprises a first filter 40 and second filter 50 inside of the bottom ofa case main body 10, and is formed with a number of first grooves 41 andsecond grooves 51 along the flowing direction of the first grooves 41 inthe first filter 40 and second filter 50, oil and oily particles thatare not removed by the second grooves 51 can be caught, thus the rangehood fan 100 can greatly reduce oil of the exhaust gas evacuated to theoutdoor from a exhaust gas duct 220 connected with the range hood fan100. As a result, by installing the range hood fan 100 of the presentinvention, the outside wall, at which the exhaust gas duct 220 opens,does not get stained and the building can be kept clean.

In addition, the range hood fan 100 according to claim 2 can give thesame effect as the above-mentioned range hood fan 100 according to claim1, and also installs the first filter 40 and second filter 50 releasablyon the inner surface of an opening and closing lid 20 placed at thelower part of the case main body 40 so that the maintenance such ascleaning or exchange of the first filter 40 and second filter 50 can beeasily performed and the durability of the range hood fan 100 can beimproved greatly.

1. A range hood fan (100), which is used in a range hood collectingoily-smoke-containing gas generated from cookers such as pots and pansduring cooking, and evacuating the oily-smoke-containing gas to theoutdoor through an exhaust gas duct, and is installed in a hood mainbody, the range hood comprising a case main body connected partly to anexhaust gas duct and forming an exhaust gas passage inside the case mainbody, a fan motor having a fan on a rotation shaft and being supportedby a partition wall in the case main body, and an exhaust gas suctionopening formed in a portion opening in the hood main body in the casemain body, the range hood further comprising a first filter beingprovided at a lower part of the case main body by net structure throughwhich the oily-smoke-containing gas can be passed and having firstgrooves extended in a rotation direction of the fan and end portions ofwhich are open in a exhaust gas passage, and a second filter providedinside the first filter, the second filter being formed by net structurethrough which the oily-smoke-containing gas can be passed and havingsecond grooves that are larger than the first grooves and end portionsof which are open in the exhaust gas passage, the first filter and thesecond filter liquefying and collecting the oily smoke of the gas byflowing the gas, which sucked from exhaust gas suction opening by a fan,along each of the second grooves and of the first grooves.
 2. The rangehood according to claim 1, wherein a bottom of the case main body havinga opening and closing lid opening a exhaust gas passage, and the firstfilter and the second filter being detachably attached on an innersurface of the opening and closing lid.